ORGLIST: folin-denis reagent

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From: Peter C. Daniel (BIOPCD$##$Mail1.Hofstra.edu)
Date: Fri Jun 01 2001 - 13:05:40 EDT


I am using the folin-denis procedure to determine total phenols in extracts but have run into a few problems somebody might be able to help me with. First, the AOAC methods states that the standard should be .1 mg/ml. When I used this I got an absorbance close to zero. In the archives of this list (posted by Jacob Zabicky 15 May) a number of replies indicated an important difference in the standard. Namely that the standard should be 10mg/mL. A web page was cited with this recipe (http://www.stanford.edu/group/Vitousek/folin.html)When I used this as the standard I got a blue-greenish solution which had an absorbance of .2 units (adding 1 ml of standard solution). That still seems a bit low to me. Any suggestions?

Peter Daniel
Dept of Biology
Hofstra University




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